Design, Implementation, and Assessment of an Undergraduate Interdisciplinary Watershed Research Laboratory

This article discusses the establishment of Shippensburg University's Burd Run Interdisciplinary Watershed Research Laboratory and the advantages of linking disciplinary perspectives across courses in geology, geography, biology, and teacher education. The laboratory provides an easily adaptable conceptual model for improving environmental science education at teaching-oriented institutions nationwide. Its success is largely attributable to three factors: the project is student-centered and goal specific; the selected watershed is accessible, diverse, and at a manageable scale; and the Laboratory Advisory Board provides for continuous revision, adaptation, and improvement. Educational levels: Graduate or professional

Storm runoff response to rainfall pattern, magnitude and urbanization in a developing urban catchment

This study explored the hydrological impacts of urbanization, rainfall pattern and magnitude in a developing catchment. The Stormwater Management Model (SWMM) was parameterized, calibrated and validated in three development phases which had a same catchment area (12.3 ha) but different land use intensities. The model calibration and validation by using sub-hourly hydro-meteorological data demonstrated a good performance of the model in predicting stormwater runoff in the different development phases. Based on the results a threshold between minor and major rainfall events was identified and conservatively determined to be about 17.5 mm in depth. Direct runoff for minor storm events has a linear relationship with rainfall; however, events with a rainfall depth greater than the threshold yields a rainfall runoff regression line with a clearly steeper slope. The difference in urban runoff generation between minor and major rainfall events diminishes with the increase of imperviousness. Urbanization leads to an increase in the production of stormwater runoff, but during infrequent major storms the runoff contribution from pervious surfaces reduces the runoff changes due to urbanization. Rainfall pattern exerts an important effect on urban runoff, which is reflected in pervious runoff. With a same magnitude, prolonged rainfall events with unvarying low intensity yield the smallest peak flow and the smallest total runoff, yet rainfall events with high peak intensity produce the largest runoff volume. These results demonstrate the different roles of impervious and pervious surfaces in runoff generation and how runoff responds to rainstorms in urban catchments depends on hyetograph and event magnitude. Furthermore, the study provides a scientific basis of the design guideline sustainable urban drainage systems, which are still arbitrary in many countries

Fate of nitrate in seepage from a restored wetland receiving agricultural tailwater

Constructed and restored wetlands are a common practice to filter agricultural runoff, which often contains high levels of pollutants, including nitrate. Seepage waters from wetlands have potential to contaminate groundwater. This study used soil and water monitoring and hydrologic and nitrogen mass balances to document the fate and transport of nitrate in seepage and surface waters from a restored flow-through wetland adjacent to the San Joaquin River, California. A 39% reduction in NO3-N concentration was observed between wetland surface water inflows (12.87±6.43mgL-1; mean±SD) and outflows (7.87±4.69mgL-1). Redox potentials were consistently below the nitrate reduction threshold (~250mV) at most sites throughout the irrigation season. In the upper 10cm of the main flowpath, denitrification potential (DNP) for soil incubations significantly increased from 151 to 2437mgNO3-Nm-2d-1 when nitrate was added, but showed no response to carbon additions indicating that denitrification was primarily limited by nitrate. Approximately 72% of the water entering the wetland became deep seepage, water that percolated beyond 1-m depth. The wetland was highly effective at removing nitrate (3866kgNO3-N) with an estimated 75% NO3-N removal efficiency calculated from a combined water and nitrate mass balance. The mass balance results were consistent with estimates of NO3-N removed (5085kgNO3-N) via denitrification potential. Results indicate that allowing seepage from wetlands does not necessarily pose an appreciable risk for groundwater nitrate contamination and seepage can facilitate greater nitrate removal via denitrification in soil compared to surface water transport alone

Aspekte van beroepsoriëntering van swart stedelike leerlinge

M.Ed. (Psychology of Education)Please refer to full text to view abstrac